As used herein, fluid means a gas, a liquid, a steam or a mixture of these. As used herein, the notion fluid is also mean to include a system consisting of a mixture of solid particles and a liquid or gas, where the mixture has fluid-like properties. One example of such a system is a suspension, e.g. a cellulose pulp suspension.
As used herein, introducing one fluid into the flow path of another fluid means injection, mixing, dispersion or other admixing of one fluid, which is also called the admixture fluid, into the flow path of the other fluid.
It is not unusual in industrial processes that fluids are mixed with each other. In e.g. the paper industry, it is not unusual that process chemicals, e.g. oxygen gas, chlorine dioxide or ozone, are introduced into a flow of pulp suspension. It is also common in this industry that steam is introduced into the flow of pulp suspension with the purpose of heating the pulp suspension.
There are a number of previously known methods and apparatuses for introducing one fluid into another fluid. One problem with these devices is that they are relatively energy intensive and that they require relatively much maintenance.
When introducing one fluid into the flow path of another fluid, it is generally always desirable to obtain a mixing or dispersion of the fluids which is as effective and uniform as possible.
One objective when injecting one fluid into another fluid, particularly when injecting steam into pulp suspension, is to admix i.e. to mix and disperse the added steam.
If the mixing or dispersion is not sufficient, there is a risk of steam bubbles forming in the liquid or suspension, wherein said steam bubbles may subsequently implode. These steam implosions cause pressure shocks in the liquid or suspension, which in their turn may propagate to machine supports, apparatuses and other process equipment and cause knocks and vibrations, which can be so powerful that mechanical damage results. This is especially a problem when a large amount of steam is added to a cellulose pulp suspension and especially to a cellulose pulp suspension of medium consistency. As used herein, a pulp suspension of medium consistency means a pulp suspension having a dry solids content in the range of approx. 8-14%.
Accordingly, there is a need to maximize and improve the mixing and dispersion of the fluids, in order to increase efficiency and minimize the risks of e.g. damaging equipment.